The present invention relates to a Biological Indicator Evaluator Resistometer (BIER) vessel system and related resistometers primarily for testing indicators, such as biological or chemical indicators, and process challenge devices in sterilization and disinfection systems.
Biological indictors are used to confirm the efficacy of a sterilization procedure, such as a vapor phase chemical sterilization system. One popular vapor phase chemical sterilization system employs vapor phase hydrogen peroxide, preferably with a plasma at some point during the exposure to hydrogen peroxide to enhance the cycle efficiency and eliminate hydrogen peroxide residuals. Other vapor phase systems include peracetic acid, ozone, chlorine dioxides ethylene dioxide and others. Instruments to be sterilized in such a cycle are typically placed into a chamber and exposed to the vapor phase sterilizing agent. To insure that the procedure worked as intended one or more biological indicators are typically included with the load.
A biological indicator typically comprises a quantity of a viable test microorganisms which if killed during the sterilization procedure indicate that it worked properly. Other indicators may also be included such as chemical exposure indicators which provide an indication of the exposure, or the level of exposure, of the load to the sterilizing agent. These indicator devices themselves must be tested to insure that they provide a standardized response which is accurate and reproducible. Such testing may include testing variations in the design or manufacturing of the indicator and production sample testing.
Further, it is often desirable to experiment with variations in sterilization cycle parameters and to examine the effects of these variations with a high degree of accuracy.
To achieve these goals, a BIER vessel is sometimes used. A BIER vessel has a first chamber in which a sterilizing atmosphere can be created and a second chamber that is isolated from the first chamber while the sterilization atmosphere is created. The first and second chambers can be quickly placed into fluid communication with each other to quickly create a known sterilization environment in the second chamber without going through a protracted process of gradually adjusting the conditions therein. For instance, rather than gradually admitting, vaporizing and diffusing a vapor phase sterilent such has hydrogen peroxide throughout a chamber, by removing a partition between the first and second chambers the vapor phase hydrogen peroxide in a first chamber will quickly establish itself within the second chamber thus creating a reliable starting time for evaluating the sterilization procedure and its effects upon a biological or chemical indicator being tested.